NEW YORK (AP) — Most women in their 40s facing the prospect of singing and dancing on Broadway eight times a week might ask to shorten their high heels just a smidge. Melanie Brown wants hers taller. No wonder they call her Scary Spice.

"If you're into high heels, you want them the higher the better," Brown said as she prepares to join the cast of "Chicago" playing the murderous Roxie Hart.

Doesn't it matter that it's a very physical role and that she'll appear for her first song on a ladder 15 feet in the air? Not to Brown.

"Why not?" she asks with a throaty laugh. "Why not?"

Brown, who since the Spice Girls' chart-topping exploits has become a sought-after TV judge, said she's relishing the chance to play a jail inmate who kills her boyfriend and sings about her newfound celebrity.

After years of criticizing others, she finds herself on stage. She seems unfazed, saying made frequent visits to the recording studio in her Los Angeles home to prepare.

"I'm always going to be the one to go, 'Yes, I just want to get back into singing,'" she said. "I'm constantly singing and vocalizing so it's nice to be able to get the chance to do it all at once."

Brown has been on Broadway before, playing Mimi in "Rent" in 2005. But this time her task has Bob Fosse-inspired choreography, skimpy outfits and killer songs such as "Me and My Baby."

"My 9-year-old said, 'Why did you choose that part? It's such a big part,'" she said. "And I'm like, "Cause it's good to challenge yourself.' And then I'm thinking, 'Why did I choose that one?'"

Brown shot to fame as part of the five-piece Spice Girls, known for its girl-power attitude thanks to songs like "Wannabe" and "Spice Up Your Life."

The group marked its 20th anniversary this year, which also happens to be the 20th anniversary of "Chicago." But Brown said none of the members managed to pull off a tour or an event to celebrate.

"I still hope something is going to happen, but nothing's been set in stone at all," she said. "We're all talking about it, but nothing's actually been said like, 'OK, on this day, on the time, this is what we're doing so let's get rehearsing!'"

Brown has been a contestant on ABC's "Dancing with the Stars" and was a judge on the Australian and UK editions of "The X Factor." She's a current judge on "America's Got Talent."

Fellow critic Simon Cowell got her involved in judging and she said she tries to concentrate simply on whoever is performing in front of her. The rest comes naturally.

"Doesn't everybody do that at home — yell at the TV and go, 'Oh my God, are you kidding me?'" she asked. "I think we all have that inside of us."